Itineraries flown on 20+ days in the Jun 6 – Jul 31, 2026 schedule · each leg’s record Aug 2025 – Jul 2026

Connect in the morning. The same 75-minute layover misses 3% of the time at 8 am and 17% of the time at 9 pm.

Nonstops


Delta	SEA	BOS	5h 26m	81%	1.6%	1,034	Flying now
Alaska	SEA	BOS	5h 27m	76%	1.0%	1,221	Flying now
JetBlue	SEA	BOS	5h 28m	55%	1.6%	247	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Boston on time. Total trip = scheduled departure to arrival, layover included (Boston is 3 h ahead of Seattle). Layovers up to 4 hours. Pick a connection for the details.


American Details →	SEA 21:35 → CLT 05:41AA 2793	3h 14m Charlotte	CLT 08:55 → BOS 11:08 +1AA 1533	10h 33m	100%	95%
Delta Details →	SEA 22:58 → ATL 06:45DL 409	1h 50m Atlanta	ATL 08:35 → BOS 11:14 +1DL 2432	9h 16m	100%	92%
United Details →	SEA 23:11 → ORD 05:18UA 747	2h 15m Chicago	ORD 07:33 → BOS 11:05 +1UA 1076	8h 54m	96%	91%
Delta Details →	SEA 23:59 → MSP 05:17DL 953	1h 38m Minneapolis	MSP 06:55 → BOS 10:45 +1DL 2649	7h 46m	97%	87%
American Details →	SEA 23:56 → ORD 06:02AA 2881	2h 28m Chicago	ORD 08:30 → BOS 12:07 +1AA 4106 · flown by Envoy	9h 11m	99%	87%
Delta Details →	SEA 17:59 → SLC 21:09DL 1165	2h 22m Salt Lake City	SLC 23:31 → BOS 06:05 +1DL 696	9h 06m	97%	87%
Southwest Details →	SEA 23:05 → MDW 05:00WN 2304	2h 40m Chicago	MDW 07:40 → BOS 10:55 +1WN 4611	8h 50m	96%	87%
United Details →	SEA 10:29 → SFO 12:47UA 1482	3h 28m San Francisco	SFO 16:15 → BOS 01:11 +1UA 2001	11h 42m	98%	86%
Tight connection: often missed
Alaska Details →	SEA 16:45 → SAN 19:36AS 1348	1h 16m San Diego	SAN 20:52 → BOS 05:40 +1AS 255	9h 55m	70%	59%
United Details →	SEA 19:05 → SFO 21:21UA 2241	1h 44m San Francisco	SFO 23:05 → BOS 08:01 +1UA 1665	9h 56m	63%	51%
United Details →	SEA 08:45 → SFO 11:03UA 2831	1h 22m San Francisco	SFO 12:25 → BOS 21:21UA 1372	9h 36m	59%	45%

Same layover, different day-part

How often the first flight arrives too late to connect (45 min minimum), for one-ticket layovers of 45–80 minutes.

Morning

SLC · 1h 20m · leaves 05:30 3%

DEN · 1h 10m · leaves 05:15 4%

DFW · 1h 15m · leaves 05:05 4%

Afternoon and evening

DFW · 57m · leaves 10:22 23%

PHL · 48m · leaves 08:20 29%

SAN · 1h 16m · leaves 16:45 30%

Delays build through the day, so an afternoon first leg eats the layover. A short connection is fine early in the morning and a gamble later on.

Mixing airlines

One ticketMiss it and the airline rebooks you; bags go through. 45 min is enough.

Separate ticketsMiss it and you buy a new ticket. Re-check bags, clear security again: we require 90 min.


Southwest WN 536 SEA 22:45 → BNA JetBlue B6 806 BNA 08:40 → BOS Connection details →	3h 40m	10h 28m	100%	91%
Alaska AS 373 SEA 16:47 → SLC Delta DL 696 SLC 23:31 → BOS Connection details →	3h 41m	10h 18m	100%	90%
Alaska AS 314 SEA 22:40 → EWR Delta DL 5764 EWR 09:30 → BOS Connection details →	2h 31m	9h 15m	98%	90%

Rank all connections, any airlines →

Regional partners count as the airline that sells them: SkyWest flying Delta Connection is one Delta ticket.

How these are worked out. Makes the connection: share of the last year’s flights where the first flight arrived with at least 45 minutes to spare (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled and arriving within 15 minutes. Not yet counted: the second flight also leaving late (which helps), gate-to-gate distance at the hub, and rebooking after a missed connection.

About this data: US DOT on-time records, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. Schedules (which flights and connections exist, and their times) are as of Jun 6 – Jul 31, 2026; seasonal flights outside that window aren’t ranked. Rebuilt monthly. JSON